1. Field of Art
This invention relates to the improvement of an agricultural combine. More specifically it relates to an improvement of the cab roof of an agricultural combine.
2. Description of Prior Art
Mechanical harvesting of grain has taken place for decades. However, efforts continue in the attempt to make harvesting operations more efficient and effective. A combine harvester generally includes a head which cuts the crop. The head then moves the cut crop into a feeder house. The feeder house lifts the cut crop into the threshing and separation areas of the combine. The grain is separated from the stalk by a rotor or threshing system. The grain is then moved and stored in a grain tank. The chaff and trash are deposited from the rear of the combine. An operator usually runs these various operations from a glass-enclosed cab. Typically, the cab is located above and behind the head. Because modem farming operations require that the combine operator be present in the cab for extended periods of time, the effort to improve the cab has been considerable. Conventional cabs are large glass-enclosed structures, usually with two seats. There are a variety of lights for observing the fanning operations during the night. Also in proximity to the cab are several mirrors for viewing the rear and sides of the combine. The placement of lights on a combine represent a great challenge. Due to the vibration created by the various threshing systems, keeping lights and mirrors dampened is difficult. It is also desirable for the operator to easily reach adjustable lights and mirrors. Because of the long hours spent operating the combine, environment control systems have also grown in importance. Most combine cabs have some form of heating, ventilation and air conditioning (HVAC) systems. Some cab designs place the HVAC units in the roof. This location sometimes results in condensation dripping into the cab. Sometimes the unit is placed above or outside the cab. This makes maintenance complicated. It is also difficult to assemble a cab roof. Typically, the interior side of the cab roof is assembled and placed in the cab. After the interior is placed in the cab, a worker must then continue to affix the various electrical components and ducting while standing on ladders outside the cab. This is complicated, tiring, time-consuming and expensive. Frequently, during the life of the combine, if maintenance is required on the cab roof, a worker must either open or remove the cab roof or climb onto the outside of cab. This is either dangerous for the worker or damaging to the seal between the roof and cab.
The prior art illustrates these and other drawbacks. U.S. Pat. No. 4,140,047 discloses a mobile cab with air filter. In order to reach the fresh air filter, a worker must climb outside the cab to a precarious position.
U.S. Pat. No. 4,185,867 discloses a harvester with a laterally extending visor structure. This visor structure is does not permit a worker to easily assemble or maintain any of the systems with the cab.
U.S. Pat. No. 4,503,749 discloses a combine visor with environmental components. This cab roof has a variety of complex cab systems which need to be installed after the roof is place on the cab. This places the assembler in the awkward position of installing equipment into the ceiling while standing in the cab. This increases the time, complexity and expense of construction. Furthermore, it is difficult to remove and attach the cab during assembly.
U.S. Pat. No. 4,660,462 discloses a ventilation system and filter. Again, the complexity HVAC system increases the time and cost to install the system. The blowers located in the roof of the cab will require that the assembler wait until after the roof is attached to the cab before starting to work. Further maintenance is accomplished from the top of the cab roof.
Consequently, the need exists for a cab roof which is easy to assemble and which allows a worker to build the roof at a `workbench` level instead of standing in a vehicle cab or on ladders outside the cab.